The `system.hostname` return the result of either `hostname -s` or
`hostnamectl --static` depending of the availability of either command.
The `system.platform` return a hash with tweaked `inspec.platform`
values:
- `system.platform[:family]` provide a family name for Arch
- `system.platform[:name]` modify `amazon` to `amazonlinux`
- `system.platform[:release]` tweak Arch and Amazon Linux:
- `Arch` is always `base-latest`
- `Amazon Linux` release `2018` is resolved as `1`
- `system.platform[:finger]` is the concatenation of the name and the
major release number (except for Ubuntu, which gives `ubuntu-20.04`
for example)
